7849122

Self-Authenticating Quantum Random Bit Generators

PublishedDecember 7, 2010
Assigneenot available in USPTO data we have
Technical Abstract

Patent Claims
20 claims

Legal claims defining the scope of protection, as filed with the USPTO.

1

1. A self-authenticating, quantum random bit generator comprising: a transmission layer including, an electromagnetic radiation source coupled to a waveguide branching into a first waveguide, a second waveguide, and a third waveguide, the electromagnetic radiation source configured to generate pulses of electromagnetic radiation in a first polarization state; two or more polarization rotators positioned and configured to rotate pulses transmitted in the second waveguide into a second polarization state and rotate pulses transmitted in the third waveguide into a third polarization state; and a system control configured to generate a sequence of bits based on polarization basis states of the pulses transmitted in the first waveguide, and tomographically authenticate randomness of the sequence of bits based on polarization basis states of the pulses transmitted in the second and third waveguides.

2

2. The generator of claim 1 further comprises an attenuator operably coupled to the first waveguide and configured to reduce the energy of the pulses transmitted in the first waveguide to at most a single photon.

3

3. The generator of claim 1 further comprises a first polarizing beamsplitter coupled to the first waveguide, a second polarizing beamsplitter coupled to the second waveguide, and a third polarizing beamspitter coupled to the third waveguide.

4

4. The generator of claim 3 wherein the first, second, and third polarizing beamsplitters split each pulse into two polarization basis states.

5

5. The generator of claim 1 wherein the electromagnetic radiation source further comprises one of: a diode laser; and a light-emitting diode coupled to a waveguide polarizer and a polarization rotator.

6

6. The generator of claim 1 wherein each polarization rotator further comprise one of: two or more polarization rotators; a half-wave plate; and a quarter-wave plate.

7

7. The generator of claim 1 wherein the system control further comprises: a pair of avalanche photodiodes configured to detect photons transmitted in the first waveguide; a first pair of p-i-n photodetectors configured to detect pulses transmitted in the second waveguide; and a second pair of p-i-n photodetectors configured to detect pulses transmitted in the third waveguide.

8

8. The generator of claim 1 wherein the system control further comprises detectors configured to detect polarization basis states of the pulses transmitting in the first, second, and third waveguides.

9

9. The generator of claim 1 wherein the waveguides further comprise one of ridge waveguides; waveguides in a photonic crystal; and optical fibers.

10

10. The generator of claim 1 wherein the transmission layer further comprises one of: silicon oxynitride; and an optical polymer.

11

11. An optoelectronic chip including the self-authenticating quantum random bit generator of claim 1 embedded within a layer of the optoelectronic chip.

12

12. A method for generating a sequence of random bits, the method comprising: generating a sequence of electromagnetic radiation pulses, each pulse in a first polarization state; splitting each pulse into a first pulse, a second pulse, and a third pulse, all three pulses in the same first polarization state; rotating each second pulse into a second polarization state and each third pulse into a third polarization state using polarization rotators; generating a sequence of bits based on detecting one of two polarization basis states of the first pulse; and based on the polarization states of the second and third pulses, performing tomographic analysis in order to authenticate the randomness of the sequence of bits.

13

13. The method of claim 12 further comprising attenuating the first pulse intensity into a single photon.

14

14. The method of claim 12 further comprising splitting the first pulse into two polarization basis states, the second pulse into two polarization basis states, and the third pulse into two polarization basis states.

15

15. The method of claim 14 wherein splitting the pulses into two polarization basis states further comprises transmitting each pulse through a polarizing beamsplitter.

16

16. The method of claim 12 wherein rotating each second pulse into a second polarization state and each third pulse into a third polarization state further comprises transmitting each second pulse through one or more polarizing beamsplitters and transmitting each third pulse through one or more polarizing beamsplitters.

17

17. The method of claim 12 wherein generating a sequence of bits further comprises assigning a bit “1” to detecting one of the two polarization basis states of the first pulse and assigning a bit “0” to detecting the other of the two polarization basis states of the first pulse.

18

18. The method of claim 12 wherein performing tomographic analysis further comprises constructing the minimum entropy: H Min ⁡ ( ρ ^ S ) ≡ - log 2 ( max x ∈ ρ ^ S ⁢ Pr ⁡ ( x ) ) where {circumflex over (ρ)} S is the density matrix for an ensemble of states | 104 i =c i |H +d i |V as a function of Stokes parameters; Pr (x) is the probability of a event x; and max x ∈ X ⁢ Pr ⁡ ( x ) means the maximum probability Pr (x) over every event x in X.

19

19. The method of claim 18 wherein the density matrix further comprises: ρ ^ S = 1 2 ⁢ ∑ i = 0 3 ⁢ S i S 0 ⁢ σ i = 1 2 ⁡ [ 1 + S 3 S 1 - iS 2 S 1 + iS 2 1 - S 3 ] where (S 0 , S 1 , S 2 , S 3 ) are Stokes parameters; the Stokes parameter S 0 is normalized to “1”; and σ 1 , σ 2 , and σ 3 are the Pauli matrices.

20

20. The method of claim 18 wherein performing tomographic analysis further comprises constructing a Toeplitz matrix T m×n based on the minimum entropy H min ({circumflex over (ρ)} S ), where m is the number of random bits, n is the number of raw bits, and m<n.

Patent Metadata

Filing Date

Unknown

Publication Date

December 7, 2010

Inventors

Marco Fiorentino
Raymond G. Beausoleil
Sean M. Spillane
Robert Newton Bicknell

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